A trench silicon carbide metal-oxide semiconductor field effect transistor includes a silicon carbide semiconductor substrate and a trench metal-oxide semiconductor field effect transistor, the field effect transistor includes a trench vertically arranged and penetrating along a first horizontal direction, a gate insulating layer formed on an inner wall of the trench, a first poly gate formed on the gate insulating layer, a shield region formed outsides and below the trench, and a field plate arranged between a bottom wall of the trench and the shield region, and the field plate has semiconductor doping and is laterally in contact to a current spreading layer to deplete electrons of the current spreading layer when a reverse bias voltage is applied.
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2. The silicon carbide semiconductor device according to claim 1, wherein the gate region has a first maximum width, the field plate has a second maximum width, the shield region has a third maximum width, and the second maximum width is smaller than the first maximum width and is smaller than the third maximum width.
This invention relates to silicon carbide (SiC) semiconductor devices, specifically addressing the design of gate regions, field plates, and shield regions to improve device performance. The problem being solved involves optimizing the dimensions of these regions to enhance electrical characteristics such as breakdown voltage, switching speed, and reliability in high-power applications. The device includes a gate region, a field plate, and a shield region, each with distinct maximum widths. The gate region has a first maximum width, the field plate has a second maximum width, and the shield region has a third maximum width. The second maximum width of the field plate is smaller than both the first maximum width of the gate region and the third maximum width of the shield region. This dimensional relationship ensures proper electric field distribution, reducing leakage current and preventing premature breakdown. The field plate, being narrower than the gate and shield regions, helps mitigate field crowding effects while maintaining efficient charge control. The shield region, with its larger width, provides additional shielding against high electric fields, further enhancing device robustness. This configuration is particularly useful in SiC-based power electronics, where high voltage and high-frequency operation are critical. The invention improves device reliability and performance by carefully balancing the widths of these critical regions.
3. The silicon carbide semiconductor device according to claim 1, wherein the gate region has a first maximum width, the field plate has a second maximum width, the shield region has a third maximum width, and the second maximum width is larger than the first maximum width and is smaller than the third maximum width.
This invention relates to silicon carbide (SiC) semiconductor devices, specifically addressing the challenge of optimizing electric field distribution and reducing switching losses in power semiconductor devices. The device includes a gate region, a field plate, and a shield region, each with distinct geometric configurations to improve performance. The gate region controls the device's switching behavior, while the field plate and shield region manage electric field distribution to prevent breakdown and enhance reliability. The field plate has a maximum width that is larger than the gate region's maximum width but smaller than the shield region's maximum width. This hierarchical width arrangement ensures efficient electric field modulation, reducing peak electric fields and minimizing switching losses. The shield region, being the widest, provides additional protection against high-voltage stress, while the narrower gate region maintains precise control over the device's conduction. This design improves the device's robustness, efficiency, and reliability in high-power applications. The invention is particularly useful in power electronics, where minimizing losses and ensuring long-term durability are critical.
4. The silicon carbide semiconductor device according to claim 1, wherein a thickness of the field plate corresponds to that of the current spreading layer.
A silicon carbide (SiC) semiconductor device includes a field plate structure designed to improve electrical performance. The device addresses challenges in high-voltage and high-power applications, such as electric vehicles and renewable energy systems, where SiC's superior properties—such as high breakdown voltage, low on-resistance, and high thermal conductivity—are leveraged. However, managing electric field distribution and reducing switching losses remain critical. The device features a field plate with a thickness matched to that of an underlying current spreading layer. The current spreading layer enhances current distribution, reducing hot spots and improving reliability. By aligning the field plate's thickness with this layer, the electric field is more uniformly distributed, preventing localized breakdown and enhancing the device's robustness. This design minimizes parasitic capacitance, improving switching speed and efficiency. The field plate also mitigates field crowding at the device edges, further enhancing breakdown voltage and reliability. The combination of these features enables the device to operate at higher voltages and frequencies while maintaining low losses, making it suitable for demanding power electronics applications.
5. The silicon carbide semiconductor device according to claim 1, wherein the trench vertically penetrates through the first semiconductor region and the third silicon carbide semiconductor layer to enable a bottom wall of the trench to be close to a bottom of the third silicon carbide semiconductor layer.
This invention relates to silicon carbide (SiC) semiconductor devices, specifically addressing the challenge of improving device performance by optimizing trench structures. The device includes a semiconductor substrate with multiple semiconductor regions and layers, where a trench is formed to vertically penetrate through a first semiconductor region and a third silicon carbide semiconductor layer. The trench is designed such that its bottom wall is positioned close to the bottom of the third silicon carbide semiconductor layer. This configuration enhances electrical characteristics by reducing resistance and improving charge carrier mobility. The trench may be filled with a conductive material to form a gate electrode, enabling efficient control of the device's switching behavior. The invention also includes a second semiconductor region adjacent to the first semiconductor region, which may serve as a drift region to support high-voltage operation. The trench's depth and proximity to the bottom of the third layer are optimized to balance electrical performance and structural integrity. This design is particularly useful in power electronics, where high efficiency and reliability are critical.
6. The silicon carbide semiconductor device according to claim 1, wherein the trench vertically penetrates through the first semiconductor region and the third silicon carbide semiconductor layer to enable a bottom wall of the trench to be close to a bottom of the current spreading layer.
A silicon carbide (SiC) semiconductor device includes a trench structure designed to enhance electrical performance. The device comprises multiple semiconductor layers, including a first semiconductor region and a third silicon carbide semiconductor layer. A trench is formed vertically through these layers, extending deep enough so that its bottom wall is positioned near the bottom of an underlying current spreading layer. This configuration improves current distribution and reduces resistance in the device. The trench may be part of a gate structure or another functional element, ensuring efficient charge carrier movement and minimizing power losses. The proximity of the trench bottom to the current spreading layer optimizes electrical conductivity and thermal management, addressing challenges in high-power SiC devices where current spreading and thermal dissipation are critical. The design leverages SiC's superior material properties, such as high breakdown voltage and low on-resistance, to enhance overall device efficiency and reliability in applications like power electronics and high-voltage systems.
7. The silicon carbide semiconductor device according to claim 1, wherein the shield region extends below the trench along the first horizontal direction to form a shield section of a continuous structure.
A silicon carbide (SiC) semiconductor device includes a trench structure with a shield region that extends below the trench in a first horizontal direction, forming a continuous shield section. This design improves electrical performance by reducing electric field concentration and enhancing breakdown voltage. The shield region is positioned to surround the trench, providing a protective barrier that mitigates leakage current and improves reliability. The continuous structure ensures uniform field distribution, preventing localized stress points that could degrade device performance. The device is particularly useful in high-power applications where SiC's superior thermal and electrical properties are leveraged for efficiency and durability. The shield region's extension below the trench optimizes charge distribution, reducing parasitic effects and improving switching characteristics. This configuration is critical for SiC devices operating under high voltage and high frequency conditions, where traditional semiconductor materials may fail. The continuous shield section ensures consistent performance across varying operating conditions, making the device suitable for power electronics, electric vehicles, and renewable energy systems. The design addresses challenges in SiC device fabrication, such as maintaining structural integrity while enhancing electrical properties.
8. The silicon carbide semiconductor device according to claim 1, wherein the shield region comprises a plurality of shield blocks which are segmentally arranged below the trench along the first horizontal direction.
A silicon carbide (SiC) semiconductor device includes a trench structure with a shield region designed to improve electrical performance. The shield region is formed below the trench and comprises multiple shield blocks that are segmentally arranged along a first horizontal direction. These shield blocks are electrically connected to each other, forming a continuous shield structure that enhances the device's breakdown voltage and reduces electric field concentration. The segmented arrangement helps mitigate stress points and improves reliability. The shield region is typically doped to create a conductive path that shields the trench from high electric fields, preventing premature breakdown. This design is particularly useful in high-power SiC devices, such as MOSFETs or IGBTs, where efficient charge carrier control and robust electrical insulation are critical. The segmented shield blocks allow for optimized field distribution while maintaining low on-resistance and high switching speeds. The overall structure ensures better thermal and electrical stability, making the device suitable for demanding applications like electric vehicles, renewable energy systems, and industrial power electronics.
9. The silicon carbide semiconductor device according to claim 8, wherein a pitch provided between the shield blocks along the first horizontal direction is in a range between 0.5 μm and 3.0 μm.
This invention relates to silicon carbide (SiC) semiconductor devices, specifically addressing the challenge of improving electrical performance and reliability in high-voltage applications. The device includes a semiconductor substrate with a drift region, a plurality of trenches extending into the substrate, and a plurality of shield blocks embedded within the trenches. Each shield block comprises a conductive material, such as polysilicon, and is insulated from the drift region by a dielectric layer. The shield blocks are arranged along a first horizontal direction, with a specified pitch between adjacent blocks ranging from 0.5 micrometers to 3.0 micrometers. This pitch range optimizes the device's ability to deplete the drift region under high-voltage conditions, reducing electric field concentrations and enhancing breakdown voltage. The shield blocks also function as field plates, further distributing the electric field and minimizing leakage current. The dielectric layer, which may include an oxide or nitride material, ensures insulation between the shield blocks and the drift region, preventing short circuits. The device may also include a gate structure adjacent to the trenches, enabling switching operations while maintaining high reliability. The combination of these features improves the device's performance in high-power and high-frequency applications, such as power electronics and electric vehicles.
10. The silicon carbide semiconductor device according to claim 1, wherein a lateral junction is formed between the field plate and the current spreading layer and has a height between 0.5 μm and 1.5 μm.
A silicon carbide (SiC) semiconductor device includes a field plate and a current spreading layer, where a lateral junction is formed between them. This junction has a height between 0.5 micrometers and 1.5 micrometers. The device is designed to improve electrical performance by optimizing the field distribution and current spreading within the semiconductor structure. The field plate helps control the electric field to prevent breakdown, while the current spreading layer ensures uniform current distribution. The specified junction height range enhances device reliability and efficiency by balancing field management and current flow. This configuration is particularly useful in high-power and high-frequency applications where SiC's superior material properties, such as high breakdown voltage and thermal conductivity, are leveraged. The lateral junction design minimizes leakage current and reduces hot carrier effects, improving overall device robustness. The device may be part of a larger semiconductor structure, such as a MOSFET or Schottky diode, where precise control of the electric field and current distribution is critical for performance. The invention addresses challenges in SiC device fabrication, including maintaining high breakdown voltages while ensuring efficient current conduction.
11. The silicon carbide semiconductor device according to claim 1, wherein the gate region and the field plate are separated from each other, and the field plate is in contact to the shield region.
A silicon carbide (SiC) semiconductor device includes a gate region and a field plate, which are physically separated from each other. The field plate is in direct contact with a shield region, which is typically a conductive or doped region designed to enhance electrical field distribution and reduce leakage current. The device is structured to improve reliability and performance in high-voltage applications by optimizing the electric field distribution across the semiconductor layers. The gate region controls the device's switching behavior, while the field plate and shield region work together to mitigate electric field concentration, preventing premature breakdown and ensuring stable operation under high-voltage conditions. This configuration is particularly useful in power electronics, where SiC devices are employed for their superior thermal conductivity and high breakdown voltage capabilities. The separation between the gate and field plate reduces parasitic capacitance, improving switching speed and efficiency, while the direct contact between the field plate and shield region enhances field management, reducing stress on the semiconductor material. The overall design aims to balance switching performance with reliability, making it suitable for applications such as inverters, converters, and power supplies.
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January 11, 2021
May 14, 2024
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